Osmanthus fragrans (Lour) flower is a typical fragrant herb in eastern countries containing multiple bioactive compounds, the extract of which has been widely used as a natural antioxidant additive in food and cosmetics. However, the existing extraction methods use organic solvents during the extraction process, which is non-eco-friendly and harmful to human health. In this study, we introduce, to our knowledge for the first time, microwave-assisted deep eutectic solvent extraction (MA-DESE) to extract antioxidant components from O. fragrans flower. The MA-DESE procedure was optimised, validated, and compared with that of traditional solvent extraction by using response surface methodology. The maximum antioxidant activity of 101.81 mg Trolox equivalent/g of dry weight was achieved at the following optimum MA-DESE parameters: microwave power, 497.12 W; microwave treatment time, 59.03 s; and solid–liquid ratio, 31.14 mL/g. In addition, UPLC-MS analysis showed a greater variety of antioxidant components, such as olivil and osmanthuside H, in O. fragrans flower extract obtained by MA-DESE than by the traditional ethanol reflux method. These results demonstrated that MA-DESE, which is safe and eco-friendly, could substitute for the conventional solvent extraction process, which is time-consuming and tedious, for the extraction of antioxidant components from O. fragrans flower.
Fangfang Zeng,Zhiwei Ge,Jarukitt Limwachiranon,Li Li,Simin Feng,Yansheng Wang,Zisheng Luo
Summary The content of bioactive phytochemicals, antioxidant activity and tyrosinase inhibitory activity of the hydroalcoholic extracts of Rosa roxburghii were determined. Yellow fruits of cultivated R. roxburghii showed the highest phenolic content (154.81 mg gallic acid g −1 ), and the green fruits of wild R. roxburghii showed higher content of flavonoid and triterpenoid. Rosa roxburghii fruits from different cultivars and maturity stages all demonstrated as good antioxidant agents and tyrosinase inhibitors, with IC50 value about twice of the positive standard in the DPPH assay and triple of the standard in the tyrosinase inhibitory activity assay. Nineteen compounds, mainly ellagic acids and its derivatives, flavonoids and their glycosides were identified by UPLC-Triple-TOF/MS analysis. As the first study of bioactive phytochemicals of R. roxburghii by UPLC-MS, the present research may provide valuable information for fulfilling the potential of R. roxburghii in the functional food area.